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1.
Food Chem ; 305: 125436, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31514047

RESUMO

The physicochemical properties of wheat bran have an effect on its technofunctional and nutritional profile. The possibility to induce physicochemical modifications in wheat bran using microfluidisation was investigated. An I-optimal experimental design was used to investigate the effect of microfluidisation processing parameters (pressure, number of passes, bran concentration and initial particle size) on important properties of wheat bran (particle size, microstructure, chemical composition, water retention capacity (WRC), extractability, viscosity and sedimentation). With the parameters used in this study, microfluidisation reduced wheat bran median particle size to 14.8 µm and disintegrated starch granules from the attached endosperm. This coincided with an increased extractability of starch and arabinoxylan. While the initial particle size was of minor importance, a higher pressure, larger number of passes and lower bran concentration during microfluidisation resulted in a smaller particle size, higher WRC and extractability, and an increased viscosity and stability in a 2% wheat bran suspension.

2.
Colloids Surf B Biointerfaces ; 184: 110489, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31522025

RESUMO

Flaxseed protein (FP) and mucilage (FM) complex bioparticles as sustainable ingredients were assembled by electrostatic interaction for plant-based Pickering stabilization of flaxseed oil (FO)-in-water emulsions. The effect of FO content (1-5 wt%) on droplet size and accelerated creaming stability of the emulsions was evaluated, from which it was found that 2.5 wt% FO emulsion had the smallest initial droplet size (i.e. D[4,3] = 8 µm) and creaming velocity (2.9 µm/s). The microstructure of the emulsions was observed using Cryo-SEM, confocal and optical microscopy, showing a thick layer of the particles on the oil surface responsible for the stabilization. The physical stability of FO emulsions stabilized by complex bioparticles against various environmental stress conditions (pH, salt and temperature) was higher compared to plain FP- and polysorbate 80-stabilized emulsions. Thus, the droplet size of FP-stabilized emulsions (pH 3) increased from 21 to 38 µm after thermal treatment (80 °C), whereas the size distribution of particle-stabilized emulsions hardly changed. The latter emulsions also remained stable during 28 days of storage and displayed good stability against a wide range of pH conditions (2-9) and salt concentrations (0-500 mM) with no sign of oiling-off. The complex particles as Pickering emulsifiers were successful to depress the FO oxidation at 4 °C and 50 °C. This study could open a promising pathway for producing natural and surfactant-free emulsions through Pickering stabilization using plant-based biopolymer particles for protecting lipophilic bioactive components.

3.
Food Res Int ; 125: 108550, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31554139

RESUMO

The unique impact of roasting conditions on the aroma quality of cocoa beans has been demonstrated in many studies. However, information on the additional impact of pod storage (PS) and its combined effect with roasting temperature (RT) is unknown. Hence, this study sought to elucidate the collective contribution of these post-harvest/process parameters on the aroma profiles of cocoa liquors produced from Forastero cocoa beans. The beans had been subjected to different treatments following a 3 × 4 full factorial experiment, consisting of PS (0, 3, 7 days) and RT (100, 120, 140, 160 °C). Statistical analysis of the results from HS-SPME-GC-MS revealed significant (p < .05) impact of both PS and RT as well as their interaction effects on the ten groups of volatiles (acids, alcohols, esters, terpenes, aldehydes, ketones, pyrazines, furans, pyrroles and others) and their overall aroma concentration. An exception was however noted for aldehydes, where the total concentration was only significantly (p < .05) influenced by the individual effects of PS and RT. A subsequent clustering of the liquors, first on the basis of all identified volatiles, then, on the basis of the odor-active volatiles, also revealed similar pattern where liquors with high RT's possessed more volatiles with higher concentrations and vice versa. More so, it seemed that no or very minimal PS treatment was necessary for preserving more aromatic volatiles with typically fruity, floral or spicy flavor notes, whereas, for liquors with volatiles exhibiting more cocoa, chocolate, nutty and roasted flavor notes, prolonged PS (> 3 days) treatment was required. These findings are expected to challenge the status-quo, specifically in the conventional ways through which the aroma potential of 'bulk' cocoa may be steered. On the one hand, the idea of manipulating PS treatment and roasting conditions may indeed consolidate the possibility of creating diverse and/or distinct aroma profiles from the same 'bulk' cocoa beans, whereas, on the other hand, it raises the question whether the Ghanaian cocoa beans - being described as 'bulk' cocoa - could be a consequence of prolonged pod storage treatment.

4.
Sci Rep ; 9(1): 9512, 2019 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-31267023

RESUMO

In this study, a double-mismatch allele-specific (DMAS) qPCR SNP genotyping method has been designed, tested and validated specifically for cacao, using 65 well annotated international cacao reference accessions retrieved from the Center for Forestry Research and Technology Transfer (CEFORTT) and the International Cocoa Quarantine Centre (ICQC). In total, 42 DMAS-qPCR SNP genotyping assays have been validated, with a 98.05% overall efficiency in calling the correct genotype. In addition, the test allowed for the identification of 15.38% off-types and two duplicates, highlighting the problem of mislabeling in cacao collections and the need for conclusive genotyping assays. The developed method showed on average a high genetic diversity (He = 0.416) and information index (I = 0.601), making it applicable to assess intra-population variation. Furthermore, only the 13 most informative markers were needed to achieve maximum differentiation. This simple, effective method provides robust and accurate genotypic data which allows for more efficient resource management (e.g. tackling mislabeling, conserving valuable genetic material, parentage analysis, genetic diversity studies), thus contributing to an increased knowledge on the genetic background of cacao worldwide. Notably, the described method can easily be integrated in other laboratories for a wide range of objectives and organisms.

5.
Food Chem ; 293: 134-143, 2019 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-31151593

RESUMO

Thymol oil-in-water nanoemulsions as a potential natural alternative for synthetic antioxidant agents were developed. The nanoemulsions were formulated using Quillaja Saponin bio-surfactant and green solvents including high oleic sunflower oil (HOSO), tricaprylin (TC), and cinnamaldehyde (CA). The 4% thymol nanoemulsions containing TC and HOSO remained stable during long-term storage (at least 30 d). The antioxidant activity (AA) of free thymol and thymol nanoemulsions was compared with butylated hydroxytoluene (BHT) and ascorbic acid. The results obtained from DPPH, FRAP, and CUPRAC antioxidant assays showed a substantial improvement (p < 0.05) of the AA of free thymol through emulsification. The outcomes from the AA of the nanoemulsions in raw chicken breast meat measured by the TBARS assay revealed a significant improvement (p < 0.05) of the AA when thymol was encapsulated. These nanoemulsions may be applicable in the food industry as well as in cosmetic and health care products.


Assuntos
Antioxidantes/química , Emulsões/química , Nanoestruturas/química , Saponinas de Quilaia/química , Tensoativos/química , Timol/química , Animais , Varredura Diferencial de Calorimetria , Galinhas , Carne/análise , Tamanho da Partícula , Quillaja/química , Quillaja/metabolismo , Sonicação
6.
Food Res Int ; 122: 411-418, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31229095

RESUMO

Since insects are a promising alternative protein source, the application potential of three insect larvae (Alphitobius diaperinus, Tenebrio molitor and Zophobas morio) for food purposes was explored. To this end, the effect of isothermal heating at 5 different temperatures (70 °C-90 °C) on structure formation in insect batters was studied rheologically. Meat batters (with the same protein content as insect batters), isothermally heated at 70 °C, were also studied for comparison. Cryo-SEM imaging was used to visualize the microstructure of raw and heated insect batters. These images showed that a network was formed in the heated batters, as well as in the raw batters. However, no clear effect of temperature or insect larva on the microstructure was observed. Rheologically, both the heating temperature applied and the insect larva used were shown to have a significant effect on the viscoelastic properties of the insect batters. Generally, batters containing Z. morio larvae showed both higher storage moduli (G') and longer linear viscoelastic regions (LVRs) compared to the other insect larvae, indicating that these larvae had the best structure forming capacities. Furthermore, both G' and the length of the LVR increased with increasing isothermal heating temperature, indicating more structure formation and structure stability in insect batters heated at higher temperatures. Compared to the meat batters, however, the insect larvae were shown to have inferior structure forming capacities. Even at the highest heating temperature (90 °C) the viscoelastic properties of the insect batters only approached those of meat batters heated at 70 °C. Therefore, it was concluded that higher heating temperatures may need to be employed in insect-based food products compared to meat products in order to obtain sufficient structure formation and the desired textural properties.

7.
Food Res Int ; 120: 504-513, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31000265

RESUMO

Diacylglycerols (DAGs) are interesting oil structuring molecules as they are structurally similar to triacylglycerols (TAGs), but are metabolized differently which results in weight loss and improved blood cholesterol levels upon dietary replacement of TAGs with DAGs. Many commercial products consist of a mixture of monoacylglycerols (MAGs) and DAGs, yet the effect of MAGs on the crystallization behavior of DAGs is still to be unraveled. Two types of commercial MAGs, one originating from hydrogenated palm stearin and one of hydrogenated rapeseed oil, were added in concentrations 1, 2 and 4% to 20% DAGs derived from hydrogenated soybean oil. Using differential scanning calorimetry, it was shown that the presence of MAGs delayed the onset of DAG crystallization. Rheological analysis revealed that MAGs also hindered crystal network development. Synchrotron X-ray diffraction analysis demonstrated that the addition of MAGs suppressed the formation of the ß form and stimulated the development of the ß' form. Likely, MAGs mainly hindered the crystallization of 1,3-DAGs, which are responsible for the development of the ß form, and stimulated the crystallization of the 1,2-DAGs, which can crystallize in the α and ß' forms. The presence of two polymorphic forms resulted in a decrease of the crystal network strength, as was derived from oscillatory rheological measurements. This research implies a different effect of monoacylglycerols on both the nucleation and crystal growth of 1,2- and 1,3-DAG isomers. This insight is not only relevant for oleogelation research, but also for emulsifying agents which often contain blends of MAGs, 1,2-DAGs and 1,3-DAGs.

8.
Food Res Int ; 120: 819-828, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31000302

RESUMO

The presence of a fat crystal network throughout the fat droplets of an oil-in-water emulsion is a requisite for partial coalescence. The characteristics of this fat crystal network determine greatly the kinetics of partial coalescence. In this study the fat crystal network was manipulated by altering the cooling rate applied to natural cream. The kinetics of partial coalescence under constant shear and at constant temperature were studied by combining rotational viscosity analysis with light microscopy and laser scattering. It was shown that slow cooling of the emulsion decelerates partial coalescence and favors the formation of loosely-packed aggregates. On the other hand, fast cooling favors a high partial coalescence rate and the formation of dense aggregates. Fat crystallization properties were analyzed using small deformation rheology, differential scanning calorimetry and cryo-scanning electron microscopy. The difference in organization of the fat crystals obtained for both cooling rates contributed significantly to the mechanistic understanding of partial coalescence as influenced by the cooling rate.

9.
Food Res Int ; 119: 84-98, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30884724

RESUMO

The impact of pod storage (PS) and roasting temperature (RT) on the aroma profiles of dark chocolates were evaluated. Cocoa liquor samples comprised of ten different combinations of PS and RT, whilst keeping the roasting time fixed at 35 min. Additionally, commercial cocoa liquors from renowned origins (Ecuador, Madagascar, Venezuela, Vietnam, Ivory Coast and Ghana) were acquired for comparison. From these, 70% dark chocolates were produced under the same conditions after which they were subjected to headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) analysis. Although both PS and RT were found to influence the aroma volatile concentrations, the impact of RT over PS seemed to be greater. An agglomerative hierarchical clustering (AHC) of all chocolates on the basis of their aroma profiles revealed a similar impact as earlier observed, where major clustering of the chocolates was in accordance with the intensity of the roasting process applied. However, within each group, the dissimilarities owing to PS among the chocolates was clearly depicted. Comparatively, chocolates with low (100-120 °C), instead of moderate to high (135-160 °C) RT's, rather showed a low dissimilarity with those from the commercial cocoa liquors of the different origins. Although from the same beans, the diversity of aroma profiles of these chocolates as well as the similitude of some treatments to some chocolates from commercial grade cocoa liquors, unequivocally underscores the possibility for steering diverse distinct flavors from 'bulk' cocoa through PS and roasting, with beneficial implications, both from an application and an economic point of view.

10.
Int J Biol Macromol ; 129: 1024-1033, 2019 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-30794898

RESUMO

Quercetin-fortified nanoparticles were prepared from almond gum (AG), a novel biological macromolecule, and Tween 80 (T80) as stabilizers and shellac (SH) as core material using an antisolvent precipitation method. The final nanoparticles were prepared by 0.67% SH, 0.02% Q, 0.5% AG and 0.1% w/v T80 using the stirring speed of 750 rpm at a dosing rate of 0.5 ml/min. The morphology of the particles was characterized using Cryo-SEM and TEM microscopy. The average particle size was 135 ±â€¯8 nm with a polydispersity index of 0.252 ±â€¯0.01 and an encapsulation efficiency of 97.7 ±â€¯1.2%. At pH 7.4 (intestinal pH), quercetin-loaded nanoparticles showed significantly (p < 0.05) higher antioxidant activity compared to free quercetin while the degradation of quercetin was lower in the nanoparticles compared to free quercetin at the similar pH. Quercetin loaded in nanoparticles was successfully found to be 2 times more available for uptake than free quercetin at pH 7.4. MTT and SRB assays revealed that no significant (p > 0.05) toxicity was observed for Caco-2 cells treated with quercetin-loaded nanoparticles with a dilution factor of 100. This study provides information about the formulation of promising nanocarriers using biological macromolecules for oral delivery of bioactive compounds.


Assuntos
Antioxidantes/química , Portadores de Fármacos/química , Nanopartículas/química , Gomas Vegetais/química , Prunus dulcis/química , Quercetina/química , Resinas Vegetais/química , Células CACO-2 , Humanos , Concentração de Íons de Hidrogênio , Polissorbatos/química
11.
Food Funct ; 10(2): 986-996, 2019 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-30702738

RESUMO

In this study, whey protein isolate (WPI)-low methoxyl pectin (LMP) electrostatic complexes were used to encapsulate quercetin (Q) in a model fat-free beverage system. The effect of the pH and WPI : LMP ratio was first studied to form soluble complexes with optimal physical properties, in terms of the hydrodynamic diameter, surface charge, and yield. Based on the results, pH 5.0 and a 2 : 1 (w/w) ratio of WPI : LMP were selected for encapsulation of Q. The stoichiometry of the binding (n) and the binding constant (Kb) of WPI:Q were evaluated at pH values of 5.0 and 7.0 at room temperature. The Q-loaded WPI:LMP nanocomplexes were produced by mixing WPI with Q at two loading concentrations corresponding to 5 : 1 and 1 : 1 WPI : Q molar mixing ratios, followed by the addition of LMP and pH adjustment to 5.0. The microstructure of Q-loaded WPI:LMP complexes was investigated by cryo-SEM imaging. Q was efficiently entrapped at two loading concentrations with an efficiency of about 97%. Q-loaded WPI:LMP complexes showed physical stability during storage and high temperature processing, as well as in the presence of challenging formulation conditions such as a high sugar concentration or salt addition (at a limited concentration). The stability of encapsulated Q against UV irradiation was approximately 4 times better than that of free Q. Moreover, Q-loaded WPI:LMP complexes were also lyophilized into dry powder, which can be useful for practical application in food products.


Assuntos
Bebidas/análise , Nanoestruturas/química , Pectinas/química , Quercetina/química , Proteínas do Soro do Leite/química
12.
Food Funct ; 10(1): 379-396, 2019 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-30604790

RESUMO

Dietary modulation can alter the gut microbiota composition and activity, in turn affecting health. Particularly, dietary fibre rich foods, such as wheat bran, are an important nutrient source for the gut microbiota. Several processing methods have been developed to modify the functional, textural and breadmaking properties of wheat bran, which can affect the gut microbiota. We therefore studied the effect of enzyme treatment, particle size reduction and wheat kernel pearling on the faecal microbiota of ten healthy individuals. The most commonly studied health marker, associated to the gut microbiota activity is Short Chain Fatty Acid (SCFA) production. This study shows that modifying wheat bran physicochemical properties allows control over the extent and the rate of SCFA production by the faecal microbiota. Wheat bran pericarp fractions, depleted in starch and enriched in cellulose and highly branched arabinoxylans, were poorly fermentable compared to unmodified wheat bran, thus resulting in a reduced SCFA production with up to 20 mM. The nature of the SCFA, however, largely depends on the donor and can be linked to the individual's gut microbiota composition. The latter changed in an individually dependent manner in response to wheat bran modification. Some product dependent significant differences could still be identified across the ten donors. This product effect is more pronounced in the microbial community attached to the wheat bran residue as compared to the luminal microbial community. Generally, we find lower levels of Firmicutes, Bacteroidetes and Bifidobacterium and a higher abundance of Proteobacteria in the pericarp enriched wheat bran fractions, compared to unmodified wheat bran.


Assuntos
Bactérias/metabolismo , Fibras na Dieta/metabolismo , Fezes/microbiologia , Microbioma Gastrointestinal , Triticum/metabolismo , Adulto , Bactérias/classificação , Bactérias/genética , Bactérias/crescimento & desenvolvimento , Fibras na Dieta/análise , Ácidos Graxos Voláteis/metabolismo , Feminino , Humanos , Masculino , Tamanho da Partícula , Triticum/química , Adulto Jovem
13.
Magn Reson Chem ; 57(9): 707-718, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-30671997

RESUMO

Water-in-oil-in-water (W/O/W) double emulsions are a promising technology for encapsulation applications of water soluble compounds with respect to functional food systems. Yet molecular transport through the oil phase is a well-known problem for liquid oil-based double emulsions. The influence of network crystallization in the oil phase of W/O/W globules was evaluated by NMR and laser light scattering experiments on both a liquid oil-based double emulsion and a solid fat-based double emulsion. Water transport was assessed by low-resolution NMR diffusometry and by an osmotically induced swelling or shrinking experiment, whereas manganese ion permeation was followed by means of T2 -relaxometry. The solid fat-based W/O/W globules contained a crystal network with about 80% solid fat. This W/O/W emulsion showed a reduced molecular water exchange and a slower manganese ion influx in the considered time frame, whereas its globule size remained stable under the applied osmotic gradients. The reduced permeability of the oil phase is assumed to be caused by the increased tortuosity of the diffusive path imposed by the crystal network. This solid network also provided mechanical strength to the W/O/W globules to counteract the applied osmotic forces.

14.
Food Res Int ; 113: 362-370, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30195530

RESUMO

Emulsion stability is desired during production, storage and transportation. However, controlled destabilization by partial coalescence is requisite in the production of e.g. whipped cream, vegetable toppings and ice cream. Partial coalescence in recombined cream (RC) implies the presence of a semisolid fat. Three types of fat, i.e. anhydrous milk fat (AMF), palm oil (PO) and palm kernel oil (PKO), were used in the production of RC. Partial coalescence was initiated by the application of shear and assessed at three temperatures, namely 15, 20 and 25 °C to investigate the relation between solid fat content (SFC) and shear-induced partial coalescence. Despite differences in SFC, shear-induced partial coalescence occurred fastest at 20 °C. On the contrary, a nearly equal SFC at 25 °C resulted in significantly different behavior amongst the fats. This demonstrates that not only SFC determines instability but also fat crystal microstructure, which is dependent on fat composition and on processing conditions. However, SFC could be related to the type of network formed by the partially coalesced fat droplets. The fat crystallization properties, studied in bulk and emulsion, point out a divergent effect of emulsification on the crystallization of the fats which could be explained by differences in crystal morphology.

15.
Food Res Int ; 111: 607-620, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30007725

RESUMO

The practice of pod storage (PS) has been applied in many cocoa producing countries, especially by Ghanaian farmers over the years. However, the study of PS has not received much attention, hence, until now, its potential impact on specific flavor precursor development and implications on the flavor of cocoa beans still remains uncovered. The study was therefore aimed at exploring this possibility through physico-chemical and flavor precursor analyses, carried out on equally fermented and dried pod stored (0, 3 and 7 days) Ghanaian cocoa beans. Flavor analysis was also conducted on equally roasted pod stored cocoa beans. Through visual assessment of the pods, pulp and beans, the compelling impact of PS on fermentation index (FI) and nib acidity could be demonstrated by the various biochemical and physical changes such as respiration, moisture reduction, and cellular degradation, occurring during the process. Whereas the entire reaction of sugar degradation may be deemed complex, a clear relationship between the FI, nib acidity and the glucose content was observed. Also, PS was found to increase with marginal increase in total reducing sugars (glucose and fructose). Although the concentration of free amino acids was directly proportional to the duration of PS, within the framework of this study, a significant difference (p < .05) was only observed in the case of extended duration (7 days). Overall, 7 PS seemed to have enhanced the formation of more volatiles. This was followed by 0 PS and finally 3 PS. Suggestively, these findings could provide some indications in explaining the typical flavor profiles of the Ghanaian cocoa beans, considering the fact that 87.8% of Ghanaian farmers adhere to this practice. Meanwhile, for the chocolate industry, the surging demand for cocoa/chocolate products exhibiting unique flavors, could be partly addressed by adopting PS as a tool for varietizing the flavor capacity of "bulk" cocoa through the expression or suppression of specific flavor precursors in the raw material on the farm level, which comes with almost no additional cost.

16.
Food Funct ; 9(7): 4036, 2018 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-29955735

RESUMO

Correction for 'Food-grade monoglyceride oil foams: the effect of tempering on foamability, foam stability and rheological properties' by Robbe Heymans et al., Food Funct., 2018, DOI: 10.1039/c8fo00536b.

17.
Nat Plants ; 4(6): 365-375, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29808023

RESUMO

Flowers have a species-specific functional life span that determines the time window in which pollination, fertilization and seed set can occur. The stigma tissue plays a key role in flower receptivity by intercepting pollen and initiating pollen tube growth toward the ovary. In this article, we show that a developmentally controlled cell death programme terminates the functional life span of stigma cells in Arabidopsis. We identified the leaf senescence regulator ORESARA1 (also known as ANAC092) and the previously uncharacterized KIRA1 (also known as ANAC074) as partially redundant transcription factors that modulate stigma longevity by controlling the expression of programmed cell death-associated genes. KIRA1 expression is sufficient to induce cell death and terminate floral receptivity, whereas lack of both KIRA1 and ORESARA1 substantially increases stigma life span. Surprisingly, the extension of stigma longevity is accompanied by only a moderate extension of flower receptivity, suggesting that additional processes participate in the control of the flower's receptive life span.

18.
Food Funct ; 9(6): 3143-3154, 2018 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-29790526

RESUMO

Foams with a continuous oil phase may be stabilized using crystalline particles. Those systems are compelling because of their potential in edible oil structuring, modifying sensorial properties and creating healthier food products. This study aimed to relate oleogel (unwhipped state) properties to oil foam (whipped state) properties using a monoglyceride-sunflower oil model system. The properties of crystal-oil mixtures were influenced by time and temperature during preparation and storage. Therefore, oleogels were prepared using different tempering protocols and their resulting microstructure was investigated with rheology, differential scanning calorimetry and X-ray diffraction. The corresponding oil foams were characterized in terms of foamability and foam stability. The properties of both systems were studied immediately after preparation as well as after 4 weeks of storage. We demonstrated that there is a large influence of the time-temperature history on the foam properties. Partially crystallized mixtures were shown to form weaker structures which capture more air because of their lower viscosity and as crystallization would preferentially take place at the interface. They were characterized by larger bubbles and were less stable and firm. It is proposed that their rheological properties are mainly dominated by interfacial contributions. Fully crystallized and stored monoglyceride-oil mixtures were seen to form stronger gel networks which included less air, contained smaller air bubbles and were stable during storage. It is hypothesized that these samples also included an important bulk gelation contribution.


Assuntos
Monoglicerídeos/química , Tensoativos/química , Cristalização , Compostos Orgânicos/química , Reologia , Temperatura Ambiente , Viscosidade , Difração de Raios X
19.
Food Chem ; 258: 237-244, 2018 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-29655728

RESUMO

Cinnamaldehyde nanoemulsions were formulated to enable its application in an aqueous environment. The pure cinnamaldehyde nanoemulsions, stabilized by polysorbate 80 (at concentrations >0.5%), had both a higher stability and smaller droplet size, whereas the emulsions containing hydrophobically modified inulin (HMI) formed a colloidal dispersion with larger particle size. Incorporation of sunflower oil (SO) allowed postponement of Ostwald ripening for a sufficiently long period of time (at least 60 days). Cryo-SEM and droplet size analyses of the nanoemulsions emulsified by HMI revealed no significant changes during storage. Under these conditions, HMI as an emulsifier exhibited a powerful resistance to high salt contents (up to 2 M) and high thermal processing temperatures (90 °C). The surfactant type and SO content had no marked influence on the antimicrobial activity of the nanoemulsions. This study provides precious information for a commercial formulation of nanoemulsions with durable physical stability under severe stress conditions.


Assuntos
Acroleína/análogos & derivados , Emulsificantes/química , Emulsões/química , Inulina/química , Nanoestruturas/química , Polissorbatos/química , Acroleína/química , Acroleína/farmacologia , Escherichia coli/efeitos dos fármacos , Interações Hidrofóbicas e Hidrofílicas , Inulina/metabolismo , Testes de Sensibilidade Microbiana , Tamanho da Partícula , Óleos Vegetais/química , Sais/química , Staphylococcus aureus/efeitos dos fármacos , Tensoativos/química , Temperatura Ambiente
20.
Food Funct ; 9(3): 1755-1767, 2018 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-29508864

RESUMO

In this study, the effect of lecithin (LEC) on the crystallization and gelation of fruit wax (FW) with sunflower oil was researched. A synergistic effect on the gel strength was observed at FW : LEC ratios of 75 : 25 and 50 : 50, compared to the corresponding single component formulations (100 : 0 and 0 : 100). Even below the critical gelling concentration (Cg) of FW, the addition of lecithin enabled gel formation. Lecithin affected the thermal behavior of the structure by delaying both crystallization and gel formation. The phospholipid acted as a crystal habit modifier changing the microstructure of the oleogel, as was observed by polarized light microscopy. Cryo-scanning electron microscopy revealed a similar platelet-like arrangement for both FW as a single oleogelator and FW in combination with LEC. However, a denser structure could be observed in the FW : LEC oleogelator mixture. Both the oil-binding capacity and the thixotropic recovery were enhanced upon lecithin addition. These improvements were attributed to the hydrogen bonding between FW and LEC, as suggested by Raman spectroscopy. We hypothesized that lecithin alters the molecular assembly properties of the FW due to the interactions between the polar moieties of the oleogelators, which consequently impacts the hydrophobic tail (re)arrangement in gelator-gelator and solvent-gelator interactions. The lipid crystal engineering approach followed here offered prospects of obtaining harder self-standing structures at a lower oleogelator concentration. These synergistic interactions provide an opportunity to reduce the wax concentration and, as such, the waxy mouthfeel without compromising the oleogel properties.


Assuntos
Lecitinas/química , Ceras/química , Cristalização , Frutas/química , Ligações de Hidrogênio , Compostos Orgânicos/química , Óleo de Girassol/química
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